Effect of liming and fertilizer on mineral content and productivity of <Emphasis Type="Italic">Brachiaria Decumbens</Emphasis> grass forage

To restore a degraded pasture of Brachiaria decumbens, located in São Carlos — SP, southeastern Brazil, under altitude tropical climate, an experiment was carried out to study the effects of limestone, buried or not buried in the soil, and fertilizer use on mineral content and forage yield, after 3 years of treatment. Limestone and phosphorus were applied once, one month before starting. NK were applied after each cutting, for fertilized plots, four to five times a year. Experimental design was a random block (100 m²), with 6 replications and 4 treatments. Each block received 4 t/ha of limestone, except the control. Forage samples were collected 14 cm above soil surface. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine the mineral contents. Dry matter yield was affected positively with liming when compared with the limestone control, but the effect of limestone use was more pronounced with the concomitant use of NK fertilizer. The contents of Ca, Cs, Fe, La, Mg, Rb, Sc, Sm and Th in forage were negatively affected with the NK use, perhaps due to a dilution effect, while a reverse were observed for K, Cl, perhaps due to input of KCl, besides Br, Mn and Se. It seems that limestone is not a key input to restore degraded tropical pastureland, grown on acid soils, when nitrogen is lacking. INAA allowed the monitoring of some not routine elements that may be under observation to avoid potential plant nutritional disorders in production systems with high limestone and fertilizer use.     

Synthesis of freestanding silica and titania-silica aerogels with ordered and disordered mesopores

Freestanding blocks of silica and titania-silica aerogels were prepared by the sol-gel method. It is possible to prepare crack-free, titania-silica aerogels with high titanium content by a careful control of the synthesis conditions. Prehydrolysis, complexation and polymer addition were used to adjust the hydrolysis and condensation rates of the silicon and titanium alkoxide precursors. Photoactive anatase TiO₂ nanocrystals with a large surface area (i.e., up to 300m²g⁻¹) were crystallized from the gel network by the high-temperature ethanol supercritical drying, and the resulting aerogel blocks were gas permeable and display a transition-regime diffusion behavior. Pore and volume shrinkages were observed in samples prepared by ethanol supercritical drying when the titanium content was increased resulting in a lower flux. Adding Pluronic P123 creates ordered mesopore domains and produces large pore aerogels even at high titanium contents. The photocatalytic oxidation reaction of trichloroethylene was performed by flowing the reactant gas mixture through the UV-irradiated aerogel blocks with excellent results.     

Evaluation of 222Rn and 226Ra concentrations in cement and limestone of Sheikh Buddin Hill,Pezu, Pakistan using different techniques

Lucky Cement Factory, Pezu is using limestone of Sheikh Buddin Hills as a raw material in cement. Workers of the factory have direct and general public have indirect exposure to radiological hazard due to natural radionuclides present in limestone. To address the radiological hazards, limestone, mixed (limestone+clay) and cement samples were evaluate for concentrations of ²²²Rn and ²²⁶Ra using CR-39, RAD7 and HPGe detectors. Maximum mean values of ²²²Rn using CR-39 and RAD7 detectors were found 1447 ± 198 and 1416 ± 74 Bq.m^?3 in cement samples and minimum were found in 536 ± 122 and 525 ± 45 Bq.m^?3 limestone samples, respectively. Maximum mean value of radon exhalation rate of 12.28 ± 1.68 Bq.m^?2 h^?1 in cement samples was found below the world average value of 57.6 Bq.m^?2 h^?1. Maximum mean values of ²²⁶Ra measured by CR-39 and HPGe detectors were found 24.25 ± 3.35 and 23.6 ± 0.70 Bq.kg^?1 in cement samples and minimum were found in 8.98 ± 2.02 and 9.19 ± 0.40 Bq.kg^?1 limestone samples, respectively. A positive correlations (R² = 0.9714) using CR-39 and RAD7 detectors and (R² = 0.9573) using CR-39 and HPGe detectors were obtained for the concentrations of ²²²Rn and ²²⁶Ra, respectively. Maximum mean value of annual effective dose of 347.78 ± 47.58 µSv.y^?1 in cement samples was found below the world average value of 1100 µSv.y^?1.     

Sulfation behavior of white mud from paper manufacture as SO<Subscript>2</Subscript> sorbent at fluidized bed combustion temperatures

The calcination characteristics, sulfation conversion, and sulfation kinetics of a white mud from paper manufacture at fluidized bed combustion temperatures were investigated in a thermogravimetric analyzer. Also, the comparison between the white mud and the limestone in sulfation behavior and microstructure was made. Although the white mud and the limestone both contain lots of CaCO₃, they are different in the alkali metal ions content and microstructure. It results in a marked difference in sulfation behavior between the white mud and the limestone. The CaO derived from white mud achieves the maximum sulfation conversion of 83% at about 940 °C which is 1.7 times higher than that derived from limestone at about 880 °C. The shrinking unreacted core model is appropriate to analyze the sulfation kinetics of the white mud. The chemical reaction activation energy E _a and the activation energy for product layer diffusion E _p for the sulfation of the white mud are 44.94 and 55.61 kJ mol⁻¹, respectively. E _p for the limestone is 2.8 times greater than that for the white mud. The calcined white mud possesses higher surface area than the calcined limestone. Moreover, the calcined white mud has more abundant pores in 4–24 nm range which is almost optimum pore size for sulfation. It indicates that the microstructure of the white mud is beneficial for SO₂ removal.     

Heating rate effect on the thermal behavior of ammonium nitrate and its blends with limestone and dolomite

The effect of heating rate on the thermal behavior of ammonium nitrate (AN) and on the kinetic parameters of decomposition of AN and its blends with limestone and dolomite was studied on the basis of commercial fertilizer-grade AN and several Estonian limestone and dolomite samples. Experiments were carried out under dynamic heating conditions up to 900 °C at heating rates of 2, 5, 10 and 20 °C min⁻¹ in a stream of dry air using Setaram Labsys 2000 equipment. For calculation of kinetic parameters, the TG data were processed by differential isoconversional method of Friedman. The variation of the value of activation energy E along the reaction progress α showed a complex character of decomposition of AN—interaction of AN with limestone and dolomite additives with the formation of nitrates as well as decomposition of these nitrates at higher temperatures.     

Pharmacophore generation,atom-based 3D-QSAR,HQSAR and activity cliff analyses of benzothiazine and deazaxanthine derivatives as dual A2A antagonists/MAO‑B inhibitors

Dual inhibition of A_2A and MAO-B is an emerging strategy in neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). In this study, atom-based three-dimensional quantitative structure–activity relationship (3D-QSAR) and hologram quantitative structure–activity relationship (HQSAR) models were generated with benzothiazine and deazaxanthine derivatives. Based on activity against A_2A and MAO-B, two statistically signi?cant 3D-QSAR models (r² = 0.96, q² = 0.76 and r² = 0.91, q² = 0.63) and HQSAR models (r² = 0.93, q² = 0.68 and r² = 0.97, q² = 0.58) were developed. In an activity cliff analysis, structural outliers were identified by calculating the Mahalanobis distance for a pair of compounds with A_2A and MAO-B inhibitory activities. The generated 3D-QSAR and HQSAR models, activity cliff analysis, molecular docking and dynamic studies for dual target protein inhibitors provide key structural scaffolds that serve as building blocks in designing drug-like molecules for neurodegenerative diseases.     

Biological Evaluation of Some Antimicrobial Nano‐Materials

N‐(benzothiazol‐2‐yl)‐2‐(piperidin‐1‐yl)acetamide derivatives ( 1‐24 ) were obtained by the reaction of 2‐chloro‐N‐(benzothiazole‐2‐yl)acetamides with piperidine derivatives. The structures of the compounds were elucidated by ¹H‐NMR and mass spectral data and elemental analysis. The compounds were screened for their antimicrobial activities against pathogenic bacteria and Candida species. The compounds were also investigated for their cytotoxic properties using MTT assay. The microbiological results revealed that the compounds were more effective against fungi than bacteria. Among Candida species, C. utilis was the most susceptible fungus to compounds 7 and 11 . It is apparent that 2,6‐dimethylpiperidine group and chloro and methyl substituents on benzothiazole ring have an important impact on anticandidal activity. MTT assay indicated that the effective doses of these derivatives were lower than their cytotoxic doses.     

Activities of Pu radionuclides and 241Am in soil samples from an alpine pasture in Romania

Activity concentrations of Pu radioisotopes and ²⁴¹Am were determined in the organic and mineral layers of four soil sections collected in 1996, providing for the first time information on the levels of these radionuclides in soil samples from Romania. The investigated site was an alpine pasture located in the Charpathian Mountains, in an area found as one of the most affected in Romania after the Chernobyl accident. In the examined soil sections radioactive inventories were estimated to be 500 Bq/m² for ²⁴¹Pu, 115 Bq/m² for ^239+240Pu, 8 Bq/m² for ²³⁸Pu and 50 Bq/m² for ²⁴¹Am. On the basis of activity ratios in the soil profile, the source of the radioactive release is discussed.     

Improved Synthesis of Oligodeoxyribonucleotides by Solid-Phase Phosphotriester Method Utilizing O6-[2-(p-Nitrophenyl)ethyl]-2′-deoxyguanosine Derivatives

The synthesis of oligodeoxyribonucleotides on a cross-linked polystyrene solid support utilizing stable mono- and dinucleotide phosphotriester building blocks is presented. The use of O⁶[2-(p-nitrophenyl)ethyl]-2′-deoxyguanosine derivatives yields cleaner DNA fragments by suppressing side reactions. Modifications improving the phosphotriester methodology are presented. The purification methods and analysis of synthetic oligodeoxyribonucleotides are described.     

Behavior of <Superscript>7</Superscript>Be and <Superscript>210</Superscript>Pb deposited via rainwater on a coniferous forest,a broad-leaved forest,and grassland

Fall water, stem flow water and falling litter in a coniferous forest (C. japonica) and a broad-leaved forest (L. edulis), and rainwater on a grassland near the forests were collected, and their ⁷Be and ²¹⁰Pb contents were measured. The average residence times of ⁷Be and ²¹⁰Pb in the forest crowns were calculated from the balances of their radionuclides, those in the forest crown of C. japonica were 88 days for ⁷Be and 9.2 years for ²¹⁰Pb, and those in the forest crown of L. edulis were 52 days and <1 year, respectively.     

Floating cultivation of marine cyanobacteria using coal fly ash

The aim of this study was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. We have investigated the viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine microalgae. The marine cyanobacterium Synechococcus sp. NKBG 040607 was found to adhere to floating CFA blocks in liquid culture medium. Maximum density of attached cells of 2.0×10⁸ cells/cm² was achieved using sea water. The marine cyanobacterium Synechococcus sp. NKBG 042902 weaklyadhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.     

Effect of acid on morphology of calcite during acid enhanced defluoridation

Fluoride removal from water by lime materials is a promising defluoridation process. Acid enhanced limestone defluoridation (AELD) technique involves precipitation of CaF₂ as well as adsorption of fluoride on the surface of limestone which is capable of reducing fluoride concentration to below the WHO guideline value of 1.5 mg/L. Acids such as acetic acid and citric acid are added to the fluoride water before filtration through limestone column to enhance the Ca²⁺ activity in solution for precipitation of fluoride as CaF₂. This paper describes the effects of these acids on the quality of the limestone during the AELD process, which has been studied to evaluate the reusability of the limestone. The reaction products that formed during the AELD process have also been analyzed. The detail study of the morphology of the limestone before and after use have been done using various analytical techniques, viz., X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The study reveals that the limestone degrades to some extent in the process due to dissolution of calcium carbonate by the acids and adsorption of fluoride by the limestone. While appreciable quantity of the citrate salt of calcium was formed in the column, the acetate salt mostly remained dissolved in the water. Since mainly the surface of the limestone particles take part in the reaction, the limestone particles can be reused for the defluoridation process after cleaning the outer surface. The limestone after use remains also suitable as raw material for cement.     

QM/MM based 3D QSAR models for potent B-Raf inhibitors

Three dimensional (3D) quantitative structure-activity relationship studies of 37 B-Raf inhibitors, pyrazole-based derivatives, were performed. Based on the co-crystallized compound (PDB ID: 3D4Q), several alignment methods were utilized to derive reliable comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) models. Receptor-guided alignment with quantum mechanics/molecular mechanics (QM/MM) minimization led to the best CoMFA model (q ² = 0.624, r ² = 0.959). With the same alignment, a statistically reliable CoMSIA model with steric, H-bond acceptor, and hydrophobic fields was also derived (q ² = 0.590, r ² = 0.922). Both models were validated with an external test set, which gave satisfactory predictive r ² values of 0.926 and 0.878, respectively. Contour maps from CoMFA and CoMSIA models revealed important structural features responsible for increasing biological activity within the active site and explained the correlation between biological activity and receptor-ligand interactions. New fragments were identified as building blocks which can replace R1-3 groups through combinatorial screening methods. By combining these fragments a compound with a high bioactivity level prediction was found. These results can offer useful information for the design of new B-Raf inhibitors.     

Oligomeric Alkoxysilanes with Cagelike Hybrids as Cores: Designed Precursors of Nanohybrid Materials

Well‐defined alkoxysilane oligomers containing a cagelike carbosiloxane core were synthesized and used as novel building blocks for the formation of siloxane‐based hybrid networks. These oligomers were synthesized from the cagelike trimer derived from bis(triethoxysilyl)methane by silylation with mono‐, di‐, and triethoxychlorosilanes ((EtO)_nMe_3?nSiCl, n=1, 2, and 3). Hybrid xerogels were prepared by hydrolysis and polycondensation of these oligomers under acidic conditions. The structures of the products varied depending on the number of alkoxy groups (n). When n=2 and 3, microporous xerogels (BET surface areas of 820 and 510 m² g^?1, respectively) were obtained, whereas a nonporous xerogel was obtained when n=1. ²⁹Si NMR spectroscopic analysis suggested that partial rearrangement of the siloxane networks, which accompanied the cleavage of the Si–O–Si linkages, occurred during the polycondensation processes. By using an amphiphilic triblock copolymer surfactant as a structure‐directing agent, hybrid thin films with a 2D hexagonal mesostructure were obtained when n=2 and 3. These results provide important insight into the rational synthesis of molecularly designed hybrid materials by sol–gel chemistry.     

Quantification of Cyclobutane Pyrimidine Dimers Induced by UVB Radiation in Conidia of the Fungi Aspergillus fumigatus,Aspergillus nidulans,Metarhizium acridum and Metarhizium robertsii

Conidia are responsible for reproduction, dispersal, environmental persistence and host infection of many fungal species. One of the main environmental factors that can kill and/or damage conidia is solar UV radiation. Cyclobutane pyrimidine dimers (CPD) are the major DNA photoproducts induced by UVB. We examined the conidial germination kinetics and the occurrence of CPD in DNA of conidia exposed to different doses of UVB radiation. Conidia of Aspergillus fumigatus, Aspergillus nidulans and Metarhizium acridum were exposed to UVB doses of 0.9, 1.8, 3.6 and 5.4 kJ m⁻². CPD were quantified using T4 endonuclease V and alkaline agarose gel electrophoresis. Most of the doses were sublethal for all three species. Exposures to UVB delayed conidial germination and the delays were directly related both to UVB doses and CPD frequencies. The frequencies of dimers also were linear and directly proportional to the UVB doses, but the CPD yields differed among species. We also evaluated the impact of conidial pigmentation on germination and CPD induction on Metarhizium robertsii. The frequency of dimers in an albino mutant was approximately 10 times higher than of its green wild-type parent strain after exposure to a sublethal dose (1.8 kJ m⁻²) of UVB radiation.     

Salt‐induced microphase separation of amorphous dendritic poly(ethylene oxide)‐block‐linear polystyrene copolymers

We prepared two block copolymers 1 and 2 consisting of a third‐generation dendron with poly(ethylene oxide) (PEO) peripheries and a linear polystyrene (PS) coil. The PS molecular weights were 2000 g/mol and 8000 g/mol for 1 and 2 , respectively. The differential scanning calorimetry (DSC) data indicated that neither of the block copolymers showed glass transition, implying that there was no microphase separation between the PEO and PS blocks. However, upon doping the block copolymers with lithium triflate (lithium concentration per ethylene oxide unit = 0.2), two distinct glass transitions were seen, corresponding to the salt‐doped PEO and PS blocks, respectively. The morphological analysis using small angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) demonstrated that a hexagonal columnar morphology was induced in salt‐doped sample 1‐Li⁺ , whereas the other sample ( 2‐Li⁺ ) with a longer PS coil revealed a lamellar structure. In particular, in the SAXS data of 2‐Li⁺ , an abrupt reduction in the lamellar thickness was observed near the PS glass transition temperature (T_g), in contrast to the SAXS data for 1‐Li⁺ . This reduction implies that there is a lateral expansion of the molecular section in the lamellar structure, which can be interpreted by the conformational energy stabilization of the long PS coil above T_g. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2372–2376, 2010     

The effects of differentiated water supply after anthesis and nitrogen fertilization on δ15N of wheat grain

The δ¹⁵N signature of plants integrates various processes in soil and plant. In this study, the effect of different water regimes applied during the period of grain growth of winter wheat on grain δ¹⁵N was examined in a 4‐year field experiment. The treatments comprised water shortage (S), an ample water supply (W), and rain‐fed crop (R). Zero fertilization (N0) and 200 kg N.ha^?1 in mineral fertilizer (N1) treatments were studied. The grain ¹⁵N was determined during grain growth and at maturity. The water regime, nitrogen application and year had a significant effect on mature grain δ¹⁵N (p < 0.001). Water and nitrogen explained 54.6% of the variability of δ¹⁵N in the experiment, the year accounted for 10.7% and the interactions for another 19.6% of the total variability. The analysis of non‐mature grain δ¹⁵N showed significant effects of N and year but not of water. Nitrogen fertilization reduced the δ¹⁵N of mature grain in years by 0.7–6.3‰ in comparison with N0 plants; the reduction was more pronounced under stress (average reduction by 4.1‰) than under rain‐fed (2.4‰) and ample water supply (2.2‰). Water stress decreased the grain δ¹⁵N in fertilized wheat, by 0.1–2.1‰ and 0.6–3.6‰ in experimental years, on average by 1.30‰ and 1.79‰ in comparison with the R and W water supply, respectively. The effect of water supply was not significant in non‐fertilized wheat. A significant negative linear relationship between grain N concentration and δ¹⁵N in maturity or during the grain growth (R² = 0.83, R² = 0.76, respectively) was found. The observed sources of grain δ¹⁵N variability should be taken into consideration when analyzing and interpreting the data on the δ¹⁵N signature of plant material from field conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Lipid Masking and Reactivation of Angiotensin Analogues

Studies on post-angioplastic restenosis have shown the implication of angiotensin II (Ang) as a myoproliferative mediator. The antiproliferative efficacy of non-peptide Ang antagonists on the rat carotid model is of 50%, whereas a continuously infused peptide antagonist at low doses totally blocks neointimal growth. To explore the feasibility of depot forms of Ang that may be introduced during angioplasty and thus prevent restenois, lipid-masked Ang analogues of the following general structure were prepared: [Xxx°, Yyy¹]Ang with Xxx = decanoyl or palmitoyl and Yyy = Ser, Cys, Asp, β-lactoyl, 3-mercaptopropanoyl or succinyl. All fatty acylated peptides [Xxx°, Yyy¹]Ang were practically inactive, and O- or S-esterified Ser and Cys peptides underwent intramolecular transcylation giving inactive N^x-acylated peptides. O-Acylated [β-mercaptopropanoyl¹]Ang were easily hydrolyzed into their biologically active[Yyy¹]Ang forms, either by mild saponification or by lipase activity.     

A Comparison of Functional Bladder Damage after Intravesical Photodynamic Therapy with Three Different Photosensitizers

Abstract— The influence of type of photosensitizer, drug and light dose, and time interval between photosensitizer and illumination on the extent of photodynamic therapy (PDT)-induced bladder damage and recovery was investigated using a mouse model. The three photosensitizers studied were Photofrin, meso-tetrahydroxyphenylchlorin (m-THPC) and bacteriochlorin a (BCA). Functional bladder damage was quantitatively assessed from increases in urination frequency index (FI) at 1-35 weeks after illumination and histological damage was qualitatively assessed at 1 day, 1, 2 and 12 weeks. Photofrin-mediated PDT caused an acute increase in FI at 1 week, with recovery within 2-8 weeks after light doses of 2.7-8.2 J/cm². After higher light doses there was only partial recovery. Previous results indicated that the acute response and rate of recovery was the same whether Photofrin was given at 1 day or up to 7 days before illumination. The m-THPC-mediated PDT at drug doses of 0.3 mg/kg also resulted in a marked acute response with good recovery, even after 10.8 J/cm². Lower drug doses in combination with 5.4 J/cm² did not result in acute or late damage. There was no significant difference in acute response when m-THPC was given 1, 3 or 7 days before illumination, although recovery was faster for the longer illumination intervals (3 or 7 days). Illumination at 1 h after 20 mg/kg BCA induced an acute response within 2 days after illumination, with recovery within 4-8 weeks. Lower drug doses did not result in damage. The most prominent histological changes during the acute period with all three photosensitizers were submucosal edema and vessel dilation, with epithelial denudation (depending on drug/light dose). We conclude that BCA and m-THPC are both potent new photosensitizers. They can induce a moderate to severe acute bladder response with complete healing over a period of a few weeks. The photosensitizer m-THPC is very effective with low doses of photosensitizer and light, whereas relatively high doses of BCA and light are required to obtain equivalent functional bladder damage in our mouse model.     

Effect of Building Block Transformation in Covalent Triazine-Based Frameworks for Enhanced CO2 Uptake and Metal-Free Heterogeneous Catalysis

Covalent triazine frameworks (CTFs) have provided a unique platform in functional material design for a wide range of applications. This work reports a series of new CTFs with two new heteroaromatic building blocks (pyrazole and isoxazole groups) through a building-block transformation approach aiming for carbon capture and storage (CCS) and metal-free catalysis. The CTFs were synthesized from their respective building blocks [(4,4′-(1H-pyrazole-3,5-diyl)dibenzonitrile (pyz) and 4,4′-(isoxazole-3,5-diyl)dibenzonitrile (isox))] under ionothermal conditions using ZnCl₂. Both of the building blocks were designed by an organic transformation of an acetylacetone containing dinitrile linker to pyrazole and isoxazole groups, respectively. Due to this organic transformation, (i) linker aromatization, (ii) higher surface areas and nitrogen contents, (iii) higher aromaticity, and (iv) higher surface basicity was achieved. Due to these enhanced properties, CTFs were explored for CO₂ uptake and metal-free heterogeneous catalysis. Among all, the isox-CTF, synthesized at 400 °C, showed the highest CO₂ uptake (4.92 mmol g⁻¹ at 273 K and 2.98 mmol g⁻¹ at 298 K at 1 bar). Remarkably, these CTFs showed excellent metal-free catalytic activity for the aerobic oxidation of benzylamine at mild reaction conditions. On studying the properties of the CTFs, it was observed that organic transformations and ligand aromatization of the materials are crucial factor to tune the important parameters that influence the CO₂ uptake and the catalytic activity. Overall, this work highlights the substantial effect of designing new CTF materials by building-block organic transformations resulting in better properties for CCS applications and heterogeneous catalysis.